@duckworp , I agree that that once you have a flat frequency response component upgrades can provide many benefits you simply can't measure with one microphone and a computer. We listen with two ears so things like soundstage can't be measured. My premise is to dial in whatever your preferred FR is before trying to change other parameters.
DSP is very limited in what it can correct. According to the paper I posted in section 2.4 Room Equalization is a Misnomer:
Equalization is very limited in what it can “correct,” yet the notion that changing the signal supplied to a sound system consisting of an unknown loudspeaker in an unknown room can “equalize” or “calibrate” a system is widespread. In the context of a practical application where there is an audience of several listeners conventional equalization cannot: • Add or remove reflections • Change reverberation time • Reduce seat-to-seat variations in bass • Correct frequency dependent directivity in loudspeakers • Compensate for frequency dependent absorption in acoustical materials and furnishings. The exception is in the highly reflective sound field at very low frequencies.